It is well known to use a coating oil to prevent rust and corrosion of metals. Particularly, these coating oils find application in coating machined articles as well as articles being processed such as sheets of cold rolled steel. These machined or processed metals are frequently stored in areas which are either high in humidity or where the atmosphere is highly corrosive. Therefore, a coating is required to prevent acid rust and corrosion.
These coatings can be classified into two broad classes. The first class is a hydrocarbon-based systems where the active ingredients are dissolved in a hydrocarbon solvent such as an alcohol, ether, alkane or olefin. The second class is water-based systems in which the active ingredients are dissolved in water. The two types of coatings should perform the same function.
The present invention is a water-based system. Prior art water-based systems have typically been formulated from a water soluble wax. When the water evaporates, the wax is left upon the surface of the article being coated. The wax is particularly undesirable in applications where the coated article is further processed. However, the water-based systems are preferred for several reasons. Since they do not use a hydrocarbon carrier, the evaporation products are basically water and hence, non-polluting. Furthermore, a water-based system is more easily biodegraded and accordingly, the potential pollution hazards are substantially reduced. A water-based system has an extremely high flash point or does not burn at all whereas a hydrocarbon-based system will easily flash. Finally, a water-based system is substantially less expensive since water is cheaper than a hydrocarbon carrier. This can be particularly important when the carrier can exceed 70% of the coating composition.
The major problem with a water-based system is maintaining the active components of the coating system in solution. This is typically referred to as compatibility. If the active components do not remain in solution, they will not uniformly coat a surface.
It is relatively easy to maintain certain coating agents in an aqueous solution, for example, water soluble waxes. But, it presents a substantial problem to provide active components in a water-based system in solution in sufficient quantity to prevent rust and acid corrosion and which do not cause a waxy buildup.